1. Field of the Invention
The present invention relates to a misalignment detecting apparatus, a misalignment detecting method, and a computer program product.
2. Description of the Related Art
Business forms such as ledgers and receipts are indispensable for business activities, and used in every facet of business including distribution and accounting. The amount of data on such forms is enormous, and technologies have been proposed to manage the data.
Recently, forms are often digitized and stored as digital data. Still, however, there are many opportunities to print the forms. Replacement of printing devices sometimes causes an error such as misalignment in printed data. Consequently, an operator has to visually check whether there is a difference before and after the replacement to check an error or the like after printing an enormous amount of form data.
In a field of medical image processing, there has been a known technology for checking a difference between two images. For example, Japanese Patent Application Laid-Open No. 2005-33656 discloses a technology in which a differential image is generated from two images.
However, in such a check by the operator, two prints are compared through visual inspection to specify a different portion. Therefore, the amount of movement of eyes is large, thereby making such comparison difficult. Also, such a check is inefficient, requiring a great deal of time and effort. Moreover, even if a differential image is generated as mentioned above, there is a problem in which it is impossible to easily ascertain which portion does not match the original image.
In one scheme, two prints are superposed each other for see-through inspection. However, the degree of transparency of paper is not high, and therefore it is difficult to check in detail. The foregoing problems also hold true not only at the time of replacement of printers but also at the time of printer development and recovery check after repair.